Capsule medical apparatus and current-carrying control method

ABSTRACT

An object of the present invention is to readily initiate an operation of a capsule medical apparatus which is inserted into a subject and executes a predetermined function. In a capsule endoscope  3  according to the present invention, a reed switch  14  connected to a power supply unit and a function executing unit is arranged parallel to a direction of a longitudinal axis t of a capsule-like casing  16  in the substantially cylindrical capsule-like casing  16  of the capsule endoscope  3.  A pair of movable electrodes of the reed switch  14  operates according to magnetic induction of a magnetic field of a magnet  6  applied substantially parallel to the direction t of the longitudinal axis of the capsule-like casing  16,  and come into contact with each other. As a result, power supply from the power supply unit to the function executing unit is allowed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/639,063, filed Dec. 14, 2006 and is based upon and claims the benefitof priority from Japanese Patent Application No. 2005-363919, filed Dec.16, 2005, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a capsule medical apparatus which isinserted inside a subject and operates on supplied power to execute apredetermined function, and a current-carrying control method thereof.

2. Description of the Related Art

In recent years, a swallowable capsule medical apparatus has beenproposed in a field of endoscope. One of the capsule medical apparatusesis a capsule endoscope which has an imaging function and a radiocommunication function provided inside a capsule-like casing. Thecapsule endoscope is swallowed by a subject (human body) from the mouthfor observation (examination), moves through inside body cavities suchas internal organs, e.g., a stomach and a small intestine, followingperistaltic movements thereof and sequentially captures images untilnaturally discharged.

Image data acquired through imaging by the capsule endoscope while thecapsule endoscope travels through the body cavities inside the body issequentially transmitted outside by radio communication, and stored in amemory provided outside. When the subject carries a receiver which isprovided with a radio communication function and a memory function, thesubject can move freely after swallowing the capsule endoscope untildischarging the same. After the capsule endoscope is discharged, adoctor or a nurse can make diagnosis by displaying images of internalorgans on a screen based on the image data stored in the memory (seeJapanese Patent Application Laid-Open No. 2003-210395).

In the capsule endoscope as described above, a reed switch, whichoperates according to an external magnetic field, is sometimes employedfor supplying power to each function executing unit from a power supply.In general, a longitudinal direction of the conventional reed switch isset vertical to a direction of a longitudinal axis of the capsuleendoscope, and a direction of a magnetic field and a lead extendingdirection of the reed switch are required to coincide with each other.

The capsule endoscope is formed rotationally-symmetrical about thedirection of the longitudinal axis, and a position in the rotationaldirection is not particularly defined. Therefore, it is difficult tomake the direction of the magnetic field and the lead extendingdirection of the reed switch coincide with each other. For example, inorder to activate the reed switch, it is necessary to move a magnetwhich generates the magnetic field around the reed switch to check theorientation of the reed switch. Thus, on/off operations of the reedswitch are cumbersome.

SUMMARY OF THE INVENTION

An object of the present invention is at least to solve the aboveproblem.

A capsule medical apparatus according to one aspect of the presentinvention includes a function executing unit that executes apredetermined function, a power supply unit that supplies power to thefunction executing unit, a main capsule body that houses the functionexecuting unit and the power supply unit, a switch that is housed in themain capsule body, that has a pair of contacts which come into contactwith each other and separate from each other according to a magneticinduction of a magnetic field applied from an outside of the maincapsule body, and that connects the function executing unit and thepower supply unit via the pair of contacts to allow conduction or toshield conduction, and a direction index that indicates a direction ofthe magnetic field which cause contact and separation of the pair ofcontacts in a manner recognizable from an outside.

A capsule medical apparatus according to another aspect of the presentinvention includes a function executing unit that executes apredetermined function, a power supply unit that supplies power to thefunction executing unit, a main capsule body that houses the functionexecuting unit and the power supply unit, and a switch that is housed inthe main capsule body, that has a pair of contacts which come intocontact with each other and separate from each other according to amagnetic induction of a magnetic field applied from an outside of themain capsule body, and that connects the function executing unit and thepower supply unit via the pair of contacts to allow conduction or toshield conduction, wherein a lead extending direction of a lead thatextends from the pair of contacts is substantially parallel to adirection of a longitudinal axis of the main capsule body.

A capsule medical apparatus according to still another aspect of thepresent invention includes a function executing unit that executes apredetermined preset function, a power supply unit that supplies powerto the function executing unit, a switch that connects the functionexecuting unit and the power supply unit so as to allow for conductionand to shield the conduction, and a main capsule body that issubstantially cylindrical in shape, that is formed in a rotationallysymmetrical shape about a direction of a longitudinal axis, and housesthe function executing unit, the power supply unit, and the switch,wherein the switch switches over a conduction state and aconduction-shielded state of the power supply unit and the functionexecuting unit according to a magnetic induction of a magnetic fieldapplied substantially parallel to the switch from outside the maincapsule body in the direction of the longitudinal axis.

A current-carrying control method of a capsule medical apparatusaccording to still another aspect of the present invention includes,when the capsule medical apparatus is provided with a main capsule bodyin which a function executing unit that executes a predeterminedfunction, a power supply unit that supplies power to the functionexecuting unit, and a switch that connects the function executing unitand the power supply unit so as to allow for conduction and shieldconduction therebetween are provided, recognizing a direction of amagnetic field which works on the switch, controlling the conduction andshielding of the conduction between the power supply unit and thefunction executing unit by making the magnetic field in a directionbased on a result of the recognizing work on the switch from the outsideof the main capsule body so as to operate the switch.

A current-carrying control method of the capsule medical apparatusaccording to still another aspect of the present invention includesarranging a switch which is connected between a function executing unitthat executes a predetermined function and a power supply unit thatsupplies power to the function executing unit, parallel to a directionof a longitudinal axis of a main capsule body, inside the main capsulebody which is substantially cylindrical in shape and is formedrotationally symmetrical in shape about the direction of thelongitudinal axis, and controlling conduction and shielding of theconduction between the power supply unit and the function executing unitby applying a magnetic field which is substantially parallel to thedirection of the longitudinal axis to the switch from an outside of themain capsule body and operating the switch according to an effect of themagnetic field.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an overall structure of a radiointra-subject information acquiring system which includes abody-insertable apparatus according to the present invention;

FIG. 2 is a sectional view showing an internal structure of a capsuleendoscope according to a first embodiment of the present invention;

FIG. 3 is an enlarged view of a structure of a reed switch in thevicinity of a magnet;

FIG. 4 is a block diagram of an example of a circuit structure of thecapsule endoscope shown in FIG. 2;

FIG. 5 is a schematic diagram illustrating a power-supply operation of areed switch according to the first embodiment;

FIG. 6 is a schematic diagram illustrating a power-supply operation of areed switch according to a modification of the first embodiment;

FIG. 7 is a sectional view showing an internal structure of a capsuleendoscope according to a second embodiment of the present invention;

FIG. 8 shows the capsule endoscope of FIG. 7 viewed from a distal-endside where an image sensor is provided;

FIG. 9 shows a capsule endoscope set in a starter according to amodification of the second embodiment, in which the capsule endoscope isviewed from a similar angle to the angle of FIG. 8;

FIG. 10 is a sectional view showing an internal structure of a capsuleendoscope according to a third embodiment of the present invention;

FIG. 11 shows the capsule endoscope of FIG. 10 viewed from a distal-endside where an image sensor is provided;

FIG. 12 is a schematic enlarged view of a structure of a reed switchwhich operates according to magnetic induction of a magnetic fieldvertical to the lead extending direction; and

FIG. 13 is a schematic enlarged view of the reed switch of FIG. 12 inwhich movable electrodes are magnetized.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Exemplary embodiments of a capsule medical apparatus and acurrent-carrying control method thereof according to the presentinvention will be described in detail below with reference to FIGS. 1 to13. It should be noted that the present invention is not limited to theembodiments below and that various modifications can be made withoutdeparting from the scope of the present invention.

First Embodiment

FIG. 1 is a schematic diagram of an overall structure of a radiointra-subject information acquiring system which includes abody-insertable apparatus according to the present invention. In thefollowing, a capsule endoscope, which is inserted into a body cavityfrom a mouth or the like of a human, i.e., a subject, and capturesimages of an examined area inside the body cavity, will be described asan example of the body-insertable apparatus of the radio intra-subjectinformation acquiring system. In FIG. 1, the radio intra-subjectinformation acquiring system includes a receiving device 2 which has aradio reception function, and a capsule endoscope 3 which is insertedinto a subject 1 to capture images such as body-cavity images and totransmit data such as an image signal to the receiving device 2.Further, the radio intra-subject information acquiring system includes adisplay device 4 which displays the body-cavity image based on the imagesignal received by the receiving device 2, and a portable recordingmedium 5 which serves for data transfer between the receiving device 2and the display device 4.

The receiving device 2 includes an antenna unit 2 a which has pluralreceiving antennas A1 to An attached onto an external surface of thesubject 1 and a main receiving unit 2 b which performs, for example,processing of a radio signal received via the plural receiving antennasA1 to An, and the antenna unit 2 a and the main receiving unit 2 b areconnected with each other in a detachable manner via a connector or thelike. Each of the receiving antennas A1 to An may be provided, forexample, in a jacket the subject 1 can wear, and the subject 1 may puton the receiving antennas A1 to An by wearing the jacket, for example.The receiving antennas A1 to An may be detachable from the jacket.Further, each of the receiving antennas A1 to An may have a main antennaunit at a distal-end portion thereof and the main antenna unit may behoused in an antenna pad which can be pasted onto the body of thesubject 1.

The display device 4 serves to display a body-cavity image or the likecaptured through imaging by the capsule endoscope 3. The display device4 may have a configuration as a workstation which displays images basedon data acquired from the portable recording medium 5. Specifically, thedisplay device 4 may directly display an image on a CRT display, aliquid crystal display, or the like, or alternatively, may be configuredto output an image onto other media as in a printer.

The portable recording medium 5 is attachable to and detachable from themain receiving unit 2 b and the display device 4, and information can beoutput from or recorded into the portable recording medium 5 when theportable recording medium 5 is mounted on the main receiving unit 2 b orthe display device 4. In the first embodiment, the portable recordingmedium 5 is inserted into the main receiving unit 2 b and records datatransmitted from the capsule endoscope 3 while the capsule endoscope 3travels through the body cavities of the subject 1. The portablerecording medium 5 is removed from the main receiving unit 2 b after thecapsule endoscope 3 is discharged from the subject 1, in other words,after the imaging inside the subject 1 is finished, and mounted onto thedisplay device 4. Then, the display device 4 reads out the data recordedin the portable recording medium 5. When the data transfer between themain receiving unit 2 b and the display device 4 is performed with theportable recording medium 5 configured with an element such as a CompactFlash® memory, the subject 1 can move more freely during the imaging ofthe body cavities compared with a case where the main receiving unit 2 band the display device 4 are connected directly by a cable. Though theportable recording medium 5 is employed for the data transfer betweenthe main receiving unit 2 b and the display device 4 in the firstembodiment, such configuration is not limiting. An embedded storage unitof a different type such as a hard disk can be provided in the mainreceiving unit 2 b, and the main receiving unit 2 b and the displaydevice 4 may be connected by a cable or by radio for data transfer.

FIG. 2 is a sectional view of an internal structure of the capsuleendoscope 3 according to the first embodiment; FIG. 3 is an enlargedview of a structure of a reed switch 14 in the vicinity of a magnetwhich is a magnetic body; and FIG. 4 is a block diagram of an example ofa circuit structure of the capsule endoscope 3 shown in FIG. 2. Thecapsule endoscope 3 includes an image sensor 30 as an informationacquiring unit provided with an illuminating unit such as an LED 11 toilluminate an interior of the body cavity of the subject 1, an imagingunit such as a CCD 12 to capture an image inside the body cavity, and anoptical system device 13 as an optical unit to focus a body-cavity imageat an imaging position of the CCD 12, and the capsule endoscope 3further includes a radio unit 17 which is provided with an RFtransmitting device 18 as a transmitter that transmits image dataacquired through imaging by the CCD 12 and an antenna 19. The imagesensor 30 and the radio unit 17 are connected via the reed switch 14 toa power supply unit 15 which serves as a power supply in such a manneras to allow conduction or shielding of the conduction. The power supplyunit 15 supplies power to the image sensor 30, the radio unit 17, andthe like. The capsule endoscope 3 is configured so that the aboveelements are arranged inside a capsule-like casing 16, which is a maincapsule body. The image sensor 30, the radio unit 17, and a signalprocessing/control unit 31 described later are respective portions of afunction executing unit 10 according to the present invention.

The reed switch 14 includes, as shown in FIG. 3, an external casing 14 aformed of a substantially cylindrical glass tube, for example, leads 14d and 14 e that serve as lead-out portions that project from theexternal casing 14 a, and movable electrodes 14 b and 14 c provided atrespective ends of the leads 14 d and 14 e inside the external casing 14a as a pair of contacts that are movable so as to contact with eachother in response to a magnetic field generated in a directionsubstantially parallel to the direction of the longitudinal axis of thecapsule endoscope 3 (capsule-like casing 16). Each of the leads 14 d and14 e and the movable electrodes 14 b and 14 c is formed with anelectrically conductive, magnetic member, and the movable electrodes 14b and 14 c are inserted into the external casing 14 a from outside so asto be arranged along a central axis of the external casing 14 a. Theleads 14 d and 14 e and the movable electrodes 14 b and 14 c aremagnetized to be opposite poles according to the magnetic induction of amagnetic field L generated by an approaching magnet 6. For example, whenthe magnet 6 is brought close as shown in FIG. 3, the lead 14 d ismagnetized to be an N-pole and the movable electrode 14 b is magnetizedto be an S-pole, while the lead 14 e is magnetized to be an S-pole andthe movable electrode 14 c is magnetized to be an N-pole. As a result ofthe magnetization, an end of the movable electrode 14 b and an end ofthe movable electrode 14 c move so as to contact with each other.

The reed switch 14 according to the first embodiment is arranged on asurface of a switching board 20 placed substantially at a center of thecapsule-like casing 16, with the longitudinal direction thereof beingparallel to a direction of a longitudinal axis t of the capsule-likecasing 16. The leads 14 d and 14 e (opposite ends of the movableelectrodes 14 b and 14 c) projecting from the external casing 14 a aresoldered to wires (not shown), for example, on the switching board 20.Thus, the reed switch 14 is electrically connected to the functionexecuting unit 10 and the power supply unit 15 via the wires. In otherwords, the reed switch 14 is arranged inside the capsule-like casing 16so that the lead extending direction of each of the leads 14 d and 14 eextending from the movable electrodes 14 b and 14 c is substantiallyparallel to the direction of the longitudinal axis t of the capsule-likecasing 16. Therefore, when the movable electrodes 14 b and 14 c arebrought into contact with each other, power is supplied from the powersupply unit 15 to the function executing unit 10 to enable an operationof each element for function execution. The reed switch 14 may bealternatively arranged on a surface of a flexible board 28 describedlater, for example, and not on the surface of the switching board 20, sothat the longitudinal direction thereof is parallel to the direction ofthe longitudinal axis t of the capsule-like casing 16.

The capsule-like casing 16 includes a transparent semi-sphericaldome-like distal-end-cover casing that covers the image sensor 30, forexample, and a cylindrical body casing that is engaged with thedistal-end-cover casing such that the image sensor 30 and the radio unit17 are arranged therein with the power supply unit 5 arrangedtherebetween while the inside of the capsule-like casing 16 maintainedin a watertight state. The capsule-like casing 16 is formed in a sizeswallowable from the mouth of the subject 1. The body casing has asemi-spherical dome-like distal-end portion formed of a colored materialwhich does not allow visible light to pass through, at an end oppositeto an opening engaged with the distal-end-cover casing.

The CCD 12 is arranged on an imaging board 21 to capture an image withina range illuminated by the illuminating light emitted from the LED 11.The optical system device 13 consists of imaging lenses that focus animage of the subject on the CCD 12. The LEDs 11 are mounted on anilluminating board 22 at six positions near and around an optical axisof the imaging lens to the right of, the left of, above, and below theoptical axis. Further, the image sensor 30 includes the signalprocessing/control unit 31 on a back side of the imaging board 21 forprocessing and/or controlling each element, as an internal control unitthat controls the image sensor 30 and the RF transmitting unit 18.Further, the switching board 20, the imaging board 21, and theilluminating board 22 are electrically connected with each other asappropriate via the flexible board 28.

The power supply unit 15 consists of two button-type batteries 24 thathave a diameter substantially equal to an inner diameter of the bodycasing, for example. As the battery 24, a silver oxide battery, arechargeable battery, a power-generating battery, or the like can beemployed. The RF transmitting device 18 is arranged on a back side of aradio board 25, for example. The antenna 19 is mounted on the radioboard 25, for example.

A circuit structure of the capsule endoscope 3 will be described withreference to FIG. 4. The capsule endoscope 3 includes: the LED 11 andthe CCD 12 as the image sensor 30; an LED driving circuit 23 thatcontrols a driven state of the LED 11, a CCD driving circuit 26 thatcontrols a driven state of the CCD 12, and a system control circuit 27that controls the operations of the LED driving circuit 23, the CCDdriving circuit 26, and the RF transmitting device 18 as the signalprocessing/control unit 31; and the RF transmitting device 18 and theantenna 19 as the radio unit 17.

The system control circuit 27 allows the capsule endoscope 3 to work sothat the CCD 12 acquires image data of an examined area illuminated bythe LED 11 while the capsule endoscope 3 is inside the subject 1. Theimage data acquired is converted into an RF signal by the RFtransmitting device 18, and the RF signal is transmitted via the antenna19 to the outside of the subject 1. Further, the capsule endoscope 3includes the battery 24 which supplies power to the system controlcircuit 27 via the reed switch 14, and the system control circuit 27 hasa function of distributing the driving power supplied from the battery24 to other elements (LED driving circuit 23, CCD driving circuit 26,and RF transmitting device 18).

Further, the capsule endoscope 3 may include a latch circuit (not shown)arranged between the power supply unit 15 and the function executingunit 10 and having the reed switch 14 as a part thereof, such that thelatch circuit is turned on in response to an input of a signal, whichserves as a control signal, generated as a result of a contact betweenthe movable electrodes 14 b and 14 c of the reed switch 14 when themagnet 6 is brought close to the reed switch 14, and that the latchcircuit is retained in an on-state thereafter to continuously supply thepower from the power supply unit 15 to the function executing unit 10.Such configuration allows for an efficient power supply without beingnegatively affected by a contact resistance between the movableelectrodes 14 b and 14 c.

When the external magnet 6 is brought close to the reed switch 14 of thecapsule endoscope 3 with the above structure, as shown in FIG. 5, whilethe external magnet 6 kept parallel to the direction of the longitudinalaxis t of the capsule-like casing 16 of the capsule endoscope 3, and themagnet 6 enters an operable range of the reed switch 14, the leads 14 dand 14 e and the movable electrodes 14 b and 14 c are magnetized to bedifferent poles (N-pole and S-pole), respectively, according to themagnetic induction of the magnetic field of the magnet 6 applied in asubstantially parallel direction to the direction of the longitudinalaxis t. The magnetization makes the movable electrodes 14 b and 14 cpulled to each other (in directions shown by solid arrows of FIG. 3) andthe movable electrodes 14 b and 14 c are brought into contact with eachother. As a result, the power supply unit 15 and the function executingunit 10 are electrically connected via the reed switch 14, to allow forthe power supply from the power supply unit 15 to the function executingunit 10.

A current-carrying control method of the capsule endoscope according tothe first embodiment will be described. First, the capsule endoscope 3is configured so that the function executing unit 10 (image sensor 30,radio unit 17, signal processing/control unit 31, and the like) and thereed switch 14 are arranged inside the capsule-like casing 16, as shownin FIG. 2 mentioned above. The reed switch 14 has the movable electrodes14 b and 14 c that are movable in response to an application of amagnetic field parallel to the extending direction of the leads. Thereed switch 14 is arranged within the capsule-like casing 16 of thesubstantially cylindrical capsule endoscope 3 which is formed in arotationally symmetrical shape about the direction of the longitudinalaxis t, so that the extending direction of the leads is substantiallyparallel to the direction of the longitudinal axis t (switch unitarranging step). The reed switch 14 is, as described earlier,electrically connected to the function executing unit 10 and the powersupply unit 15.

Then, the magnet 6 arranged outside the capsule endoscope 3 is broughtcloser to or away from the reed switch 14 in order to magneticallyoperate the reed switch 14, whereby a conduction state or aconduction-shielded state of the function executing unit 10 and thepower supply unit 15 via the reed switch 14 is controlled(current-carrying control step). In the current-carrying control step,the magnet 6 arranged outside the capsule endoscope 3 is brought closerto the reed switch 14 while the direction of magnetic field of themagnet 6 is kept substantially parallel to the direction of thelongitudinal axis t of the capsule-like casing 16, as shown in FIGS. 3and 5. When the magnet 6 enters the operable range of the reed switch14, the movable electrodes 14 b and 14 c of the reed switch 14 aremagnetized to be different poles (N-pole and S-pole) according to themagnetic induction of the magnet 6 which generates a magnetic fieldapplied substantially parallel to the direction of the longitudinal axist. The magnetization causes the movable electrodes 14 b and 14 c to bepulled towards each other and to contact, and as a result, the powersupply unit 15 and the function executing unit 10 that have been in theconduction-shielded state are brought into an electrically connectedstate (conduction state) via the reed switch 14. While in the conductionstate, the power can be supplied from the power supply unit 15 to thefunction executing unit 10.

As can be seen from the foregoing, in the first embodiment, the magnet 6outside the capsule endoscope 3 is brought close to the reed switch 14while the magnetic field and the direction of the longitudinal axis t ofthe capsule-like casing 16 are maintained substantially parallel to eachother; the movable electrodes 14 b and 14 c are brought into operationand made to contact with each other according to the magnetic inductionof the magnetic field of the magnet 6 applied substantially parallel tothe extending direction of the leads of the reed switch 14; whereby thepower supply from the power supply unit 15 to the function executingunit 10 is allowed. Therefore, the on/off operations of the reed switchcan be realized without the need of confirmation of the orientation ofthe reed switch, and the operation of the capsule endoscope (morespecifically, the operation of the function executing unit 10) can beinitiated securely and easily.

Modification of First Embodiment

FIG. 6 is a schematic diagram of a modification of the first embodimentand given for a description of the power supply operation of the reedswitch 14. In the modification of the first embodiment as shown in FIG.6, the magnet 6 is brought closer to the capsule endoscope 3 from thedistal-end side where the image sensor 30 is provided, so that themagnetic field of the magnet 6 works on the reed switch 14 arranged inthe capsule-like casing 16 in the direction substantially parallel tothe direction of the longitudinal axis t of the capsule-like casing 16of the capsule endoscope 3.

In the modification of the first embodiment, as described above, themagnet 6 outside the capsule endoscope 3 is brought closer to thecapsule endoscope 3 from the distal-end side; the movable electrodes 14b and 14 c are brought into operation and made to contact with eachother according to the magnetic induction of the magnetic field of themagnet 6 applied substantially parallel to the reed switch 14; wherebythe power supply from the power supply unit 15 to the function executingunit 10 is allowed. Therefore, similarly to the first embodiment, theon/off operations of the reed switch can be realized without the need ofconfirmation of the orientation of the reed switch, and the operation ofthe capsule endoscope (more specifically the operation of the functionexecuting unit 10) can be initiated securely and easily. Depending onthe strength of the magnetic field, the magnet 6 may be brought close tothe capsule endoscope 3 from a back-end side where the radio unit 17 isprovided, for example. The current-carrying control method of thecapsule endoscope according to the modification of the first embodimentis the same as that of the first embodiment.

Second Embodiment

FIG. 7 is a sectional view of an internal structure of the capsuleendoscope 3 according to a second embodiment of the present invention;and FIG. 8 is a sectional view of the capsule endoscope 3 shown in FIG.7 viewed from the distal-end side where the image sensor 30 is provided.In the second embodiment, as shown in FIGS. 7 and 8, the reed switch 14is arranged on the switching board 20 provided substantially at thecenter of the capsule endoscope 3 as in the conventional apparatus, sothat the longitudinal direction of the reed switch 14 (i.e., theextending direction of the leads) is vertical to the direction of thelongitudinal axis of the capsule-like casing 16 of the capsule endoscope3. In other respects, the structure of the second embodiment is the sameas the structure of the first embodiment, and the same element will bedenoted by the same reference character.

As shown in FIG. 8, on a front face of the disk-like illuminating board22, two triangular indexes 35 a and 35 b are arranged within anexternally recognizable range along with six LEDs 11. The indexes 35 aand 35 b indicate in a manner recognizable from the outside thedirection of the magnetic field of the magnet 6 necessary to make themovable electrodes 14 b and 14 c, i.e., a pair of contacts of the reedswitch 14, move (i.e., move towards each other or away from each other).Specifically, the indexes 35 a and 35 b show, in a recognizable manner,the orientation (direction of N-pole and S-pole) of the magnet 6 at thetime the magnet 6 is brought close to the capsule-like casing 16 to makethe movable electrodes 14 b and 14 c of the reed switch 14 move towardseach other or away from each other to switch over the on/off states ofthe power supply from the power supply unit 15 to the function executingunit 16. Further, the indexes 35 a and 35 b show the extending directionof leads of the reed switch 14 arranged inside the capsule-like casing16 at the same time. An operator can easily recognize the direction ofthe magnet 6 (i.e., direction of a magnetic field applied to the reedswitch 14) approaching the capsule-like casing 16 and the extendingdirection of the leads of the reed switch 14 (angle formed by a centralaxis of the reed switch 14 and the direction of the longitudinal axist), by visually checking the indexes 35 a and 35 b. The indexes 35 a and35 b may be formed on the surface of the illuminating board 22 at thetime of manufacture of the illuminating board 22, or may formed as aprinted pattern through printing on the board surface.

The magnet 6 is brought close to a predetermined position which issubstantially at the center of the capsule endoscope 3 based on theindexes 35 a and 35 b (for example, the magnet 6 is brought closesubstantially to the center of the capsule endoscope 3 while the S-poleend and the N-pole end of the magnet 6 are kept aligned with the indexes35 a and 35 b, respectively, as shown in FIG. 8). Then, the leads 14 dand 14 e and the movable electrodes 14 b and 14 c of the reed switch 14are magnetized to be different poles according to the magnetic inductionof the magnetic field of the magnet 6, and the magnetization causes oneend of the movable electrode 14 b and one end of the movable electrode14 c to move and contact with each other.

A current-carrying control method of the capsule endoscope according tothe second embodiment will be described. As shown in FIG. 7 mentionedabove, the capsule endoscope 3 is formed so that the function executingunit 10 (image sensor 30, radio unit 17, signal processing/control unit31, and the like) and the reed switch 14 are arranged inside thecapsule-like casing 16. The reed switch 14 has the movable electrodes 14b and 14 c that are movable in response to an application of a magneticfield parallel to the extending direction of the leads. The reed switch14 is arranged within the capsule-like casing 16 of the substantiallycylindrical capsule endoscope 3 which is formed in a rotationallysymmetrical shape about the direction of the longitudinal axis t, sothat the extending direction of the leads is substantially vertical tothe direction of the longitudinal axis t (switch unit arranging step).Then, the direction of the magnetic field (i.e., the direction of themagnetic field of the magnet 6 which approaches the reed switch 14 fromoutside the capsule endoscope 3) which works on the reed switch 14 isvertical to the direction of the longitudinal axis t of the capsule-likecasing 16. The reed switch 14 is electrically connected to the functionexecuting unit 10 and the power supply unit 15, as described above.

Then, the operator recognizes the direction of the magnetic field of themagnet 6 that works on the reed switch 14 by visually checking theindexes 35 a and 35 b formed on the capsule endoscope 3 (morespecifically on the illuminating board 22) (direction recognizing step).As shown in FIG. 8, the indexes 35 a and 35 b are formed on theilluminating board 22 inside the capsule endoscope 3 to indicate in avisually recognizable manner the direction of the magnetic field of themagnet 6 (direction of the N-pole and the S-pole of the magnet 6) thatworks on the reed switch 14 to move the movable electrodes 14 b and 14 cof the reed switch 14 towards each other or away from each other, tocontrol the conduction state or the conduction-shielded state of thefunction executing unit 10 and the power supply unit 15.

Thereafter, the magnet 6 is brought close to or taken away from the reedswitch 14 at the outside of the capsule endoscope 3 so as tomagnetically operate the reed switch 14, whereby the conduction state orthe conduction-shielded state of the function executing unit 10 and thepower supply unit 15 is controlled via the reed switch 14(current-carrying control step). In the current-carrying control step,as shown in FIG. 8, the magnet 6 is brought close to the predeterminedposition substantially at the center of the capsule endoscope 3 whilethe S-pole and the N-pole of the magnet 6 is kept aligned with theindexes 35 a and 35 b as described above. When the magnet 6 enters theoperable range of the reed switch 14, the magnetic field, which issubstantially parallel to the extending direction of the leads of thereed switch 14 (i.e., a direction substantially vertical to thedirection of the longitudinal axis t), is applied to the reed switch 14from the magnet 6, and the movable electrodes 14 b and 14 c of the reedswitch 14 are magnetized to be different poles (N-pole, S-pole)according to the magnetic induction of the magnetic field of the magnet6. The magnetization causes the movable electrodes 14 b and 14 c to bepulled towards each other to contact, and as a result, the power supplyunit and the function executing unit 10 that have been in theconduction-shielded state are brought into an electrically connectedstate (conduction state) via the reed switch 14. While in the conductionstate, the power supply from the power supply unit 15 to the functionexecuting unit 10 is allowed.

As can be seen from the foregoing, in the second embodiment, the indexes35 a and 35 b are arranged within the range recognizable from outsidethe capsule endoscope 3 so as to indicate the direction of the magneticfield of the magnet 6 necessary for moving (bringing in contact witheach other or separating from each other) the movable electrodes 14 band 14 c, i.e., a pair of contacts of the reed switch 14. When themagnet 6 is brought close to the reed switch 14 in such a manner thatthe direction indicated by the indexes 35 a and 35 b is keptsubstantially equal to the direction of the magnetic field, then, themagnetic field of the external magnet 6 is applied to the reed switch 14in a direction parallel to the extending direction of the leads, wherebythe movable electrodes 14 b and 14 c can be moved and brought intocontact with each other according to the magnetic induction of themagnetic field. As a result, the power supply from the power supply unit15 to the function executing unit 10 is allowed. Therefore, the operatorcan easily check the orientation of the reed switch from the outside torealize the on/off operations of the reed switch, whereby the operationof the capsule endoscope (more specifically, the operation of thefunction executing unit 10) can be initiated securely and easily.

In the second embodiment, the direction of the magnetic field of themagnet 6 (i.e., orientation of the reed switch 14) is indicated by theindexes 35 a and 35 b. The present invention, however, is not limitedthereto, and the direction of the magnetic field of the magnet 6 can beindicated by a change in position or direction of other elements. As anexample of such modification according to the present invention, aspecific LED 11 among the LEDs 11 may be arranged such that thelongitudinal direction thereof is aligned with a predetermined radialdirection of the disk-like illuminating board 22 as shown by a dottedline in FIG. 8, so that the specific LED 11 indicates the direction ofthe magnetic field of the magnet 6 (orientation of the reed switch 14).When such modification is adopted, the LED 11 is preferably arrangedoutside a range of visual field which is determined depending on opticalcharacteristics of the imaging lens focusing the subject image on theCCD 12.

In the above, the description of the second embodiment is provided basedon the reed switch which operates according to the magnetic field. Othertypes of switches are conceivable, however, such as a switch whichoperates by sensing ultraviolet rays, heat, or the like. Therefore, theindex of the second embodiment is applicable as an element thatindicates a position of one of the above switches to specify a positionto irradiate the ultraviolet rays or the heat.

Modification of Second Embodiment

FIG. 9 shows the capsule endoscope 3 set in a starter 40 according to amodification of the second embodiment, and is a section viewed from thesame direction as that of FIG. 8. In the modification of the secondembodiment shown in FIG. 9, the indexes 35 a and 35 b arranged on thefront face of the illuminating board 22 are the same as those of thesecond embodiment. The modification is different from the secondembodiment in that the magnet 6 is arranged on the starter 40 and thatan index 41 is arranged on the starter 40 in such a manner that theindex 41 consisting of a triangular pattern indicating a position wherethe magnet 6 is arranged is aligned with the center of the magnet 6. Inother respects, the structure of the modification is the same as that ofthe second embodiment, and the same component will be denoted by thesame reference character.

In the modification of the second embodiment, the capsule endoscope 3 isset in the starter 40, and the magnet 6 is brought close to thepredetermined position determined based on the indexes 35 a and 35 b ofthe capsule endoscope 3 (for example, the index 41 of the starter 40 ispositioned right at the middle of two indexes 35 a and 35 b of thecapsule endoscope 3 as shown in FIG. 9), so that the capsule endoscope 3is driven, whereby the extending direction of the leads of the reedswitch 14 becomes substantially parallel to the direction of themagnetic field of the magnet 6, and the leads 14 d and 14 e of the reedswitch 14 and the movable electrodes 14 b and 14 c are magnetized to bedifferent poles according to the magnetic induction of the magneticfield of the magnet 6. The magnetization causes one end of the movableelectrode 14 b and one end of the movable electrode 14 c to move andcontact with each other.

As can be seen from the foregoing, in the modification of the secondembodiment, the indexes 35 a and 35 b are arranged within the rangerecognizable from the outside of the capsule endoscope 3 so as toindicate the direction of the magnetic field to be applied to the reedswitch 14, and further, the index 41 is arranged on the starter 40 inwhich the capsule endoscope 3 is set so as to indicate the positionwhere the magnet 6 is to be arranged. When the magnet 6 is brought closeto the predetermined position determined based on the indexes 35 a, 35b, and 41, the magnetic field of the magnet 6 in the starter 40 isapplied in a direction parallel to the extending direction of the leadsof the reed switch 14 similarly to the second embodiment, whereby themovable electrodes 14 b and 14 c are moved and made to contact with eachother according to the magnetic induction of the magnetic field. As aresult, the power supply from the power supply unit 15 to the functionexecuting unit 10 is allowed. Therefore, the operator can easily checkthe orientation of the reed switch from outside to realize the on/offoperations of the reed switch, whereby the operation of the capsuleendoscope (more specifically, the operation of the function executingunit 10) can be initiated securely and easily.

In the modification of the second embodiment, the single index 41 isprovided in the starter 40. The present invention, however, is notlimited thereto. For example, indexes 42 a and 42 b shown by a dottedline in FIG. 9 may be provided on an extension from the center of thedisk-like illuminating board 22 passing through the indexes 35 a and 35b in a predetermined radial direction. At the time of the power supplyto the function executing unit 10, the starter 40 or the capsuleendoscope 3 may be shifted so that the indexes 42 a and 42 b arepositioned at the predetermined radial direction (i.e., so that theindexes 35 a and 35 b on the side of the capsule endoscope 3 and theindexes 42 a and 42 b on the side of the starter 40 are arranged in thepredetermined positional relation, so that the magnetic induction of themagnetic field of the magnet 6 works on the movable electrodes of thereed switch 14.

A current-carrying control method of the capsule endoscope according tothe modification of the second embodiment is similar to thecurrent-carrying control method of the second embodiment except that thedirection of the magnetic field (direction of the magnet 6) relative tothe reed switch 14 is recognized through visual confirmation of theindex (e.g., indexes 35 a and 35 b) of the capsule endoscope side andthe index (e.g., index 41 or indexes 42 a and 42 b) of the starter sideat the direction recognizing step.

Third Embodiment

FIG. 10 is a sectional view of an internal structure of the capsuleendoscope 3 according to a third embodiment of the present invention.FIG. 11 is a sectional view of the capsule endoscope 3 shown in FIG. 10viewed from the distal-end side where the image sensor 30 is provided.As shown in FIG. 10, the capsule endoscope 3 according to the thirdembodiment includes a reed switch 54 which performs on/off operationsaccording to the magnetic induction of a magnetic field which issubstantially vertical to the extending direction of leads, in place ofthe reed switch 14 (which makes the movable electrodes 14 b and 14 ccontact with each other or separate from each other according to themagnetic induction of the magnetic field parallel to the extendingdirection of leads) described above. Further, as shown in FIG. 11, twotriangular indexes 35 a and 35 b are arranged within a rangerecognizable from the outside together with six LEDs 11 on the frontsurface of the disk-like illuminating board 22. The indexes 35 a and 35b indicate in a manner recognizable from outside the direction of themagnetic field of the magnet 6 necessary to make the pair of contacts ofthe reed switch 54 contact with each other or separate from each other.In the third embodiment, the indexes 35 a and 35 b show the directionvertical to the direction of the longitudinal axis t of the capsule-likecasing 16 (i.e., radial direction of the capsule-like casing 16) as thedirection of the magnetic field of the magnet 6 approaching the reedswitch 54 from outside the capsule-like casing 16. In other words, whenthe magnetic field is to be applied to the reed switch 54, the magnet 6is brought close to the capsule endoscope 3 while the direction of themagnetic field is kept vertical to the direction of the longitudinalaxis t (see FIGS. 10 and 11). In other respects, the structure of thethird embodiment is the same as the structure of the first embodiment,and the same element will be denoted by the same reference character.

The reed switch 54 of the capsule endoscope 3 according to the thirdembodiment of the present invention will be described. FIG. 12 is aschematic enlarged view of the structure of the reed switch 54 whichoperates according to the magnetic induction of the magnetic fieldvertical to the extending direction of the leads. FIG. 13 is a schematicenlarged view of the reed switch 54 shown in FIG. 12 in a state wherethe movable electrodes are magnetized.

As shown in FIG. 12, the reed switch 54 includes an external casing 14 awhich consists of a substantially cylindrical glass tube or the like,leads 14 d and 14 e that extend from the external casing 14 a, andmovable electrodes 54 b and 54 c arranged inside the external casing 14a and connected to the leads 14 d and 14 e, respectively. The movableelectrodes 54 b and 54 c are ends of the leads 14 d and 14 e,respectively, and work as a pair of contacts that is brought intocontact according to the magnetic induction of the magnetic fieldsubstantially vertical to the direction of the longitudinal axis t ofthe capsule-like casing 16. The movable electrodes 54 b and 54 c are,similarly to the leads 14 d and 14 e, formed of an electricallyconductive, magnetic material, and inserted from the outside into theexternal casing 14 a along the central axis thereof for the arrangement.

The movable electrodes 54 b and 54 c are magnetized to be differentpoles along a direction of layers (thickness direction of the electrode)according to the magnetic induction of the magnetic field L generated bythe approaching magnet 6. Specifically, as shown in FIG. 13, the movableelectrodes 54 b and 54 c are magnetized so that the N-pole and theS-pole are alternately layered along the thickness direction of theelectrode according to the magnetic field of the magnet 6 applied in thedirection vertical to the direction of the longitudinal axis t of thecapsule-like casing 16. A face of the movable electrode 54 b and a faceof the movable electrode 54 c facing with each other are magnetized tobe different poles. For example, as shown in FIG. 13, an opposing faceon the movable electrode 54 b side is magnetized to the S-pole, whereasan opposing face on the movable electrode 54 c side is magnetized to theN-pole. When the movable electrodes 54 b and 54 c are magnetized to bedifferent poles along the direction of layers, the movable electrodes 54b and 54 c move as if being pulled towards each other and contact asshown by solid arrows in FIGS. 12 and 13.

The reed switch 54 having the above structure is arranged on the surfaceof the switching board 20 so that the extending direction of leads issubstantially parallel to the direction of the longitudinal axis t ofthe capsule-like casing 16, similarly to the reed switch 14 of the firstembodiment described earlier. Here, the leads 14 d and 14 e of the reedswitch 54 are soldered to wires (not shown), for example, on theswitching board 20, and are electrically connected to the functionexecuting unit 10 and the power supply unit 15 via the wires. When themovable electrodes 14 b and 14 c of the reed switch 54 contactmagnetically with each other as described above, the power from thepower supply unit 15 is supplied to the function executing unit 10 viathe reed switch 54 so as to enable the operation of each element forfunction execution. Alternatively, the reed switch 54 can be arranged onthe surface of the flexible board 28 rather than on the switching board20 so that the extending direction of the leads is substantiallyparallel to the direction of the longitudinal axis t of the capsule-likecasing 16.

In the third embodiment, the indexes 35 a and 35 b indicate in a mannerrecognizable from outside the direction of the magnetic field of themagnet 6 necessary to make the movable electrodes 54 b and 54 c, i.e.,the pair of contacts of the reed switch 54, operate (contact with eachother or separate from each other). Specifically, the indexes 35 a and35 b show, in a visually recognizable manner, the direction of themagnet 6 (direction of the N-pole and the S-pole) at the time the magnet6 is brought close to the capsule-like casing 16 to make the movableelectrodes 54 b and 54 c of the reed switch 54 contact with each otheror separate from each other for the switching of the on/off state of thepower supply from the power supply unit 15 to the function executingunit 10. The operator can easily recognize the direction of the magnet 6approaching the capsule-like casing 16 (direction of the magnetic fieldto be applied to the reed switch 54) by visually checking the indexes 35a and 35 b.

As exemplified by the indexes 35 a and 35 b, a direction indexindicating the direction of the magnetic field applied to the reedswitch 54 can be arranged at any position as far as the index can bevisually recognized from outside of the capsule endoscope 3. Forexample, the index may be formed on an outer wall of the capsule-likecasing 16 and not on the illuminating board 22 mentioned above.

When the magnet 6 is brought close to a predetermined positionsubstantially at the center of the capsule endoscope 3 based on theindexes 35 a and 35 b (for example, when an S-pole end of the magnet 6is brought close to a substantial center of the capsule endoscope 3while the direction from the N-pole to the S-pole of the magnet 6 iskept substantially aligned with the direction from the index 35 a to theindex 35 b as shown in FIGS. 10 and 11), the movable electrodes 54 b and54 c of the reed switch 54 are magnetized to be different poles alongthe layer direction according to the magnetic induction of the magneticfield of the magnet 6, and as a result of the magnetization, the movableelectrodes 54 b and 54 c move so that the opposing faces thereof comeinto contact with each other.

A current-carrying control method of the capsule endoscope according tothe third embodiment will be described. As shown in FIG. 10 mentionedabove, the capsule endoscope 3 is formed so that the function executingunit 10 (image sensor 30, radio unit 17, signal processing/control unit31, and the like) and the reed switch 54 are arranged inside thecapsule-like casing 16. The reed switch 54 has the movable electrodes 54b and 54 c that are movable in response to an application of a magneticfield vertical to the extending direction of the leads. The reed switch54 is arranged within the capsule-like casing 16 of the substantiallycylindrical capsule endoscope 3 which is formed in a rotationallysymmetrical shape about the direction of the longitudinal axis t, sothat the extending direction of the leads is substantially parallel tothe direction of the longitudinal axis t (switch unit arranging step).Here, the direction of the magnetic field which works on the reed switch54 (i.e., the direction of the magnetic field of the magnet 6 which isbrought close to the reed switch 54 from outside the capsule endoscope3) is vertical to the direction of the longitudinal axis t of thecapsule-like casing 16. The reed switch 54 is electrically connected tothe function executing unit 10 and the power supply unit 15 as describedabove.

Then the operator recognizes the direction of the magnetic field of themagnet 6 which works on the reed switch 54 by visually checking theindexes 35 a and 35 b formed on the capsule endoscope 3 (e.g.,illuminating board 22) (direction recognizing step). The indexes 35 aand 35 b are, as shown in FIG. 11, formed on the illuminating board 22inside the capsule endoscope 3, and show in a visually recognizablemanner the direction of the magnetic field of the magnet 6 (i.e., thedirection of the N-pole to the S-pole of the magnet 6) which works onthe reed switch 54 to make the movable electrodes 54 b and 54 c of thereed switch 54 contact with each other or separate from each other tocontrol the conduction state or the conduction-shielded state of thefunction executing unit 10 and the power supply unit 15.

Thereafter, the magnet 6 outside the capsule endoscope 3 is broughtclose to or away from the reed switch 54 to magnetically operate thereed switch 54, whereby the conduction state or the conduction-shieldedstate between the function executing unit 10 and the power supply unit15 via the reed switch 54 is controlled (current-carrying control step).In the current-carrying control step, as shown in FIG. 11, the directionfrom the N-pole to the S-pole of the magnet 6 is aligned with thedirection from the index 35 a to the index 35 b, when the magnet 6 isbrought close to a predetermined position substantially at the center ofthe capsule endoscope 3. When the magnet 6 enters the operable range ofthe reed switch 54, the magnetic field which is substantially verticalto the extending direction of leads (i.e., substantially vertical to thedirection t of the longitudinal axis t) of the reed switch 54 is appliedto the reed switch 54 from the magnet 6, and the surfaces of the movableelectrodes 54 b and 54 c of the reed switch 54 opposite to each otherare magnetized to be different poles (N-pole, S-pole), respectively,according to the magnetic induction of the magnetic field of the magnet6. Due to the magnetization, the movable electrodes 54 b and 54 c arepulled toward each other, and as a result, the power supply unit 15 andthe function executing unit 10 are turned from the conduction shieldedstate to the electrically connected state (conduction state) via thereed switch 54. In the conduction state, the power supply from the powersupply unit 15 to the function executing unit 10 is allowed.

Thus, in the third embodiment, the indexes 35 a and 35 b are provided soas to indicate the direction of the magnetic field of the magnet 6necessary to move (to bring close to or to separate) the movableelectrodes 54 b and 54 c which is a pair of contacts of the reed switch54 within a range recognizable from outside the capsule endoscope 3.When the magnet 6 is brought close to the reed switch 54 so that thedirection defined by the indexes 35 a and 35 b is substantially equal tothe direction of the magnetic field, the direction of the magnetic fieldof the external magnet 6 becomes vertical to the extending direction ofleads of the reed switch 54. Then, the magnetic field is applied in theabove direction to the reed switch 54, whereby the movable electrodes 54b and 54 c can be made to move and contact with each other according tothe magnetic induction of the magnetic field. As a result, the powersupply from the power supply unit 15 to the function executing unit 10is allowed, and the orientation of the reed switch can be easilyconfirmed from the outside so as to cause the on/off operations of thereed switch to securely and readily start the operation of the capsuleendoscope (specifically, to start the operation of the functionexecuting unit 10).

In the third embodiment, the direction of the magnetic field of themagnet 6 is indicated by the indexes 35 a and 35 b. The presentinvention, however, is not limited thereto, and the direction of themagnetic field of the magnet 6 may be indicated via a change in positionor orientation of other element, similarly to the second embodimentdescribed above.

Further, though the reed switch which is operable according to themagnetic field is described in the third embodiment, other switch whichoperates by sensing ultraviolet rays or heat, for example, may beemployed, and the index of the second embodiment can be applied to anelement which indicates the position of such a switch to specify aposition which is to be irradiated with the ultraviolet rays or theheat.

The capsule medical apparatus and the current-carrying control method ofthe present invention define the direction of the magnetic field in avisually recognizable manner based on the direction of the longitudinalaxis of the capsule-like casing or the direction index, and the switchconnects the function executing unit and the power supply unit to allowconduction or to shield the conduction according to the magnetic fieldof the direction defined; thus, the capsule medical apparatus and thecurrent-carrying control method of the present invention areadvantageous in that the operation of the function executing unit of thecapsule medical apparatus can be readily started.

In the first to the third embodiment and the modifications describedabove, electric current is made to flow from the power supply unit 15 tothe function executing unit 10 for the power supply. The presentinvention, however, is not limited thereto, and the present inventioncan be applied to a structure in which the similar operation serves toshield the conduction from the power supply unit 15 to the functionexecuting unit 10, thereby stopping the power supply.

Further, in the first to the third embodiments and the modificationsdescribed above, the capsule endoscope (an example of the capsulemedical apparatus serving as the body-insertable apparatus) whichacquires images in a living body is described. The present invention,however, is not limited thereto, and the present invention can beapplied to a capsule medical apparatus which acquires information suchas pH and temperature of the living body in the living body, exertingthe similar effect and advantage as those obtained in the first to thethird embodiments and the modifications described above.

Further, in the first to the third embodiments and the modificationsdescribed above, the magnet 6 that applies the magnetic field to theswitch (e.g., reed switches 14 and 54) that connects the power supplyunit and the function executing unit to allow conduction or to shieldthe conduction can be a permanent magnet or an electromagnet.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

INDUSTRIAL APPLICABILITY

As can be seen from the foregoing, the capsule medical apparatus and thecurrent-carrying control method according to the present invention areuseful for a capsule medical apparatus which is provided with a switchthat switches the connection state between the function executing unitand the power supply unit according to the magnetic field, and inparticular, are suitable for a capsule medical apparatus and acurrent-carrying control method which allows for easy visualconfirmation of the direction of the magnetic field applied to theswitch based on the direction of the longitudinal axis of thecapsule-like casing or the direction index so as to allow for a readilyinitiation of the operation of the function executing unit.

1. A capsule medical apparatus comprising: a function executing unitthat executes a predetermined function; a power supply unit thatsupplies power to the function executing unit; a main capsule body thathouses the function executing unit and the power supply unit; and aswitch that is housed in the main capsule body, that has a pair ofcontacts which come into contact with each other and separate from eachother according to a magnetic induction of a magnetic field applied froman outside of the main capsule body, and that connects the functionexecuting unit and the power supply unit via the pair of contacts toallow conduction or to shield conduction, wherein a lead extendingdirection of a lead that extends from the pair of contacts issubstantially parallel to a direction of a longitudinal axis of the maincapsule body.
 2. A capsule medical apparatus comprising: a functionexecuting unit that executes a predetermined preset function; a powersupply unit that supplies power to the function executing unit; a switchthat connects the function executing unit and the power supply unit soas to allow for conduction and to shield the conduction; and a maincapsule body that is substantially cylindrical in shape, that is formedin a rotationally symmetrical shape about a direction of a longitudinalaxis, and houses the function executing unit, the power supply unit, andthe switch, wherein the switch switches over a conduction state and aconduction-shielded state of the power supply unit and the functionexecuting unit according to a magnetic induction of a magnetic fieldapplied substantially parallel to the switch from outside the maincapsule body in the direction of the longitudinal axis.
 3. The capsulemedical apparatus according to claim 2, wherein the switch is a reedswitch, and a lead extending direction of the reed switch issubstantially parallel to the direction of the longitudinal axis.
 4. Thecapsule medical apparatus according to claim 1, wherein the switch hastwo electrodes that are magnetized to different poles according to themagnetic induction of the magnetic field applied substantially parallelto the switch from the outside of the main capsule body in the directionof the longitudinal axis, and the two electrodes connect the powersupply unit and the function executing unit so as to allow forconduction and to shield the conduction by moving and coming intocontact with each other according to the magnetization to differentpoles.
 5. A current-carrying control method of the capsule medicalapparatus, comprising: arranging a switch which is connected between afunction executing unit that executes a predetermined function and apower supply unit that supplies power to the function executing unit,parallel to a direction of a longitudinal axis of a main capsule body,inside the main capsule body which is substantially cylindrical in shapeand is formed rotationally symmetrical in shape about the direction ofthe longitudinal axis; and controlling conduction and shielding of theconduction between the power supply unit and the function executing unitby applying a magnetic field which is substantially parallel to thedirection of the longitudinal axis to the switch from an outside of themain capsule body and operating the switch according to an effect of themagnetic field.
 6. The current-carrying control method of the capsulemedical apparatus according to claim 5, further comprising recognizing adirection of the magnetic field which works on the switch based on thedirection of the longitudinal axis, wherein the controlling includescontrolling the conduction and the shielding of the conduction betweenthe power supply unit and the function executing unit by applying themagnetic field in the direction recognized in the recognizing to theswitch from the outside of the main capsule body and operating theswitch according to the effect of the magnetic field.
 7. Thecurrent-carrying control method of the capsule medical apparatusaccording to claim 5, wherein the controlling includes controlling theconduction and the shielding of the conduction between the power supplyunit and the function executing unit by applying the magnetic fieldwhich is substantially parallel to the direction of the longitudinalaxis to the switch that has electrodes made respectively of two magneticbodies and forming a pair of contactable and separable contacts, andbringing the electrodes into contact with each other by magnetizing theelectrodes to different poles according to an effect of the magneticfield.